Often interim certificates are issued where itemised components of the work have been completed, or are a verifiable percentage complete.

The builder must pay the nominated sub-contractor the amount certified within I 7 days of the date of issue of the interim certificate.

The builder's surveyor will be unable to certify payments to the various nominated subcontractors until after the interim certificate has been received from the architect.

If payments are to be certified the builder's surveyor may delay the issue of the documentation until the interim certificate for the main contract is received from the architect.

At each interim valuation the builder will pass the original nominated invoices received during the month to the quantity surveyor for inclusion in the interim certificate and payment.

(b) The contractor has the obligation to pay the nominated subcontractor the sums directed by the architect and included in the interim certificate, less the agreed retention and cash discount.

Theoretically, under clause 30.1.1.1, the contractor is entitled to payment by the client within 14 days from the date of issue of each interim certificate, thus providing three days of grace.

The client's quantity surveyor, and if necessary the relevant consultant, will also check the invoices or payment requests and include the agreed amount for each nominated sub-contractor in the interim certificate.

(c) The contractor is obliged under clause 35.13.3, before the issue of each interim certificate, to provide the client's quantity surveyor with reasonable proof that the payments authorised to nominated subcontractors in the previous certificate have been made.

When contra-charges or claims have arisen between the builder and the nominated sub-contractor for such items as damage, breakages or delays then obviously the amount certified by the builder will vary from that certified in the interim certificate.

The Film Production Company (FPC) responsible for the production of the film can apply for an interim certificate that the film is British at any point before or during production, to BFI.

If the FPC does not submit a final certificate, then any FTR paid on the basis of the interim certificate is no longer due and will have to be repaid to the HMRC by the FPC.

The grant of an interim certificate by the Civil Aeronautics Board (CAB) in October 1962 to operate domestic military contract flights, intrastate and overseas charters from 1 April 1963 was followed by further fleet expansion, including the lease of another L-1049 and the purchase of an L-749A in 1964.